Thesis (M.S.) -- Mississippi State University. Department of Biological Sciences. / Title from title screen. Includes bibliographical references.

This thesis concerns a study into the relationship between vegetation structure and breeding birds in the dry subzone of the Interior Douglas fir BiogeocIimatic Zone. The study was conducted in the East Kootenay region of southeastern British Columbia. Studies of bird/habitat relationships often relate bird densities with successional vegetation; for management purposes it is convenient to view habitat alterations as changes from one successional stage to-another. Theoretical questions concerning the effect of succession and disturbance on species richness can be approached in this way. Also, there has been considerable interest in the effect of snags on bird density. An analysis of the effect of stumps and snags on bird density was incorporated into the study. Three questions guided the study: (1) What is the relationship between breeding birds and successional vegetation? (2) How is vegetation structure related to successional changes in bird species densities? (3) How does the number of stumps and snags affect the numbers of cavity nesting birds? There were two land management practices which altered the vegetation structure in the study area: selective logging and spring burning. This enabled me to determine the effects of these practices on breeding birds and to extend knowledge of the relationship between birds and vegetation structure. Twenty-four 300 yd by 400 yd (274 by 366 m) plots were established representing replications of each successional stage, transitions between successional stages, a selectively logged mature seral forest, a burned scrubby area, and a burned grassland/scrubby transition area. Bird data were recorded during fourteen, 20 minute visits to each plot in May and June of 1977. All birds detected by sight and sound were recorded during each visit to a plot. The vegetation data gathered on each plot included: estimates of the number of stumps and snags and estimates of crown coverage in each height zone of all species of grass, forb, shrub, and tree. The height zones recognized were 0-.5 m, .5-1 m, 1-10m, 10-24 m, and 24+ m. Multiple step-wise correlation was used to relate breeding bird densities with vegetation structure. Data from only the 25 most commonly recorded bird species were used to describe changes in the bird community with changes in vegetation succession. Results showed: (1) Bird species were non-randomly distributed with respect to successional stages. (2) Most successional stages support a unique compliment of bird species. (3) In general bird abundance was greater with greater successional age of a plot. However, dense stands of young conifer and climax Douglas fir forest had lower bird densities than the successional stages immediately preceding them. Mature serai ponderosa pine/Douglas fir forests had the highest bird densities. In some cases the bird densities on scrubby plots were comparable to the ponderosa pine/Douglas fir plots. (4) The relationship between bird species and vegetation structure is somewhat complex, but in general, visually obvious vegetation structures (i.e. height and coverage of grass, shrubs, and trees) are related to the presence of bird species. The species of trees and shrubs on a site can be used as an indicator of the bird species present. (5) The presence of cavity nesting birds was not closely linked with stumps and snags. Stumps and snags may not be a limiting resource. (6) The bird community on a grass dominated site which was burned in April 1977 was strikingly similar to that of another unburned grass dominated site. There were differences, among the bird communities on burned and unburned scrubby areas which were consistent with the recent fire history of the sites. (7) The selectively logged plot had numbers of bird species and bird species diversity similar to those of unlogged mature seral ponderosa pine/Douglas fir forest. The density of individual birds was lower on the logged plot than on the unlogged plots. Some bird species became more plentiful and others less plentiful as a result of the logging, but the bird community on the logged plot was composed of species associated with forested successional stages. A number of recommendations have been made for further study of East Kootenay bird/habitat interactions through a policy of experimental management. / Science, Faculty of / Zoology, Department of / Graduate

This study is an analysis of the various factors affecting the population of raptorial birds on Sauvie Island, Oregon. A census of diurnal and nocturnal raptors was carried out along with an analysis of food habits. Once the major prey species were determined they were censused, and the effects of the land management practices on their numbers was investigated. In addition, 100 randomly selected nest boxes were sampled so as to determine the extent to which raptors were making use of them. Red-tailed hawk and Great Horned Owl nests were located It was found that four diurnal raptors and three nocturnal raptors were present in sizeable numbers on Sauvie during the winter and spring of 1972. In addition here were less common sightings of four diurnal and one nocturnal raptor. The most common food item of raptors in general was the vole, Microtus townsendi, which was later found to be present in extremely high numbers. The common practice of planting fields of grains and the intentional flooding of them (for waterfowl use) was found to be a major factor in the numbers and vulnerability of Microtus townsendi. Ducks were a common food item for all raptorial species during and immediately after duck hunting season, but not at any other time of year which seemed to indicate that the raptors were feeding on carrion or wounded ducks. It was found that Barn Owls (Tyto alba), Screech Owls (Otis asio) and Kestrel (Falco sparvarius) made use of the nest boxes on Sauvie Island. The overlapping of food habits of Sauvie Island raptors was discussed and an attempt was made to reconcile the apparent contradiction to Gause’s Rule.

Det sker stora förändringar i de regional likt globala fågelbestånden. I Sverige sker både ökningar och minskningar av populationerna, vilket orsakas av flera olika faktorer. En av dessa är tillgången på föda. Därför är syftet med denna studie att undersöka om avslutad fågelmatning någon påverkan på ett lokalt fågelbestånd.Fågelsamhället på Fredriksdals museer och trädgårdar i Helsingborg studerades medstandardiserade revirkarteringar med en anpassad linjekartering av området under perioden 2017–2022. De faktorer som undersöks är förhållandet mellan de arter som förekommer vid matning eller ej, förhållandet mellan stann- och flyttfåglar samt utvecklingen av det totala antalet arter och par under undersökningsperioden. Resultatet visar att det totala antalet fåglar på Fredriksdal minskat med 50% under de senaste sex åren medan antalet arter varit stabilt. Det observerades ingen signifikant skillnad i minskningen av de fåglar som förekommer vid matning och gruppen som inte förekommer vid matningen. Det fanns inte heller någon signifikant skillnad mellan minskningen av de övervintrande fåglarna och flyttfåglarna. Dessa båda grupper visade en stabil negativ trend över undersökningsperioden. Detta betyder att den upphörda fågelmatningen kan ha påverkat bestånden negativt men det är isfallbara för enskilda arter och det kan inte förklara den totala minskningen. Några delförklaringar till den negativa trenden är klimatförändringarna som på global nivå påverkar fågelbestånden, förändringar i habitat både på Fredriksdal och på flyttfåglarnas övervintringslokaler och minskad tillgång på föda främst på grund av det minskande antalet insekter i hela Europa. / There are major changes in regional as well as global bird populations. In Sweden, there are both increases and decreases in populations, which is caused by several different factors. One of these is the availability of food. Therefore, the purpose of thisstudy is to investigate whether completed bird feeding at Fredriksdal's museums and gardens in Helsingborg has any impact on the local bird population. The method used is standardized area mapping with an adapted line mapping of the area during the period 2017–2022. The factors investigated are the ratio between the species that occur when feeding or not, the ratio between resident and migratory birds and the development of the total number of species and pairs during the study period. The result shows that the total number of birds at Fredriksdal has decreased by 50% over the past six years, while the number of species has remained stable. No significant difference was observed in the reduction of the birds present at feeding and the group not present at feeding. There was also no significant difference between the decline of wintering birds and migratory birds. These two groups showed a stable negative trend over the survey period. This means that the cessation of bird feeding may have had a negative effect on the populations, but it is icefall only for individual species and it cannot explain the overall decline. Some partial explanations for the negative trend are the climate changes that affect bird populations on a global level, changes in habitat both at Fredriksdal and at the migratory birds' wintering grounds as well as reduced availability of food mainly due to the decreasing number of insects throughout Europé.

I sampled bird densities and habitat characteristics along a gradient from a second-order stream to 454 m upland at 16 locations. Total bird density, species richness, and densities of 28 bird species were tested to determine whether riparian habitats influenced bird communities. Total bird density and species richness showed no riparian influence. Acadian flycatchers and Louisiana waterthrushes were closely linked to the streams. Carolina wrens, American robins, and red-eyed vireos showed weaker but positive associations with the streams. Eastern wood-pewees, black-and-white warblers, pine warblers, worm-eating warblers, and scarlet tanagers demonstrated a negative association with streams. A cluster analysis was used to group the 28 bird species into 5 assemblages based on their distribution among the sampling stations. The species were classified as belonging to the following assemblages: riparian, upland forest, mesic hardwoods, xeric forest, and mature hardwoods generalist. Logistic models were developed to predict the number of species in each assemblage that were present and the presence of each species at each station based on the habitat characteristics at the site. Regression models were developed to predict the relative abundance of each assemblage and species at occupied stations. / Master of Science

Relationships between the breeding bird populations of the southern Appalachian cove hardwood and mixed oak-pine habitat types were studied during the 1977 and 1978 breeding seasons, in Craig County, Virginia. Relationships between habitat structure and bird utilization for each of the 12 most common breeding species were also investigated. Bird and habitat data were collected within 100 meter x 50 meter transect areas. Eleven transects were located in the mixed oak-pine habitat and 8 in cove hardwood habitat. Relative density and species diversity of the 2 bird communities were essentially the same. Species composition was similar; however, relative dominance structures of the 2 communities were different. The blue-gray gnatcatcher (Polioptila caerulea), red-eyed vireo (Vireo olivaceus) and worm-eating warbler (Helmitheros vermivorus) exhibited a significant preference for the cove hardwood habitat. The ovenbird (Seiurus aurocapillus) exhibited a significant preference for the mixed oak-pine habitat, and the pine warbler (Dendroica pinus) and rufous-sided towhee (Pipilo erythrophthalmus) were observed exclusively in the mixed oak-pine areas. The relative density of the singing males was significantly greater in 1978 than in 1977. Multiple discriminant and regression analyses were used to analyze species/habitat associations. Eighty habitat components were considered for inclusion in these analyses. The "best" models derived for each species were presented and all were significant at the 0.05 level. Each species' association with the surrounding forest was best characterized by different combinations of habitat components, suggesting that resource division was adequately described through vegetative community structure. Research needs and potential uses for this type of data in nongame bird management were discussed. / Master of Science

No description available.

The sooty shearwater (also known as the muttonbird, Titi, Puffinus griseus) is a long-lived super-abundant, burrow nesting petrel, harvested by Rakiura Maori from breeding colonies, located in southern New Zealand. The harvest is culturally defining and enormously important for Rakiura Maori. The work in this thesis contributes to the Kia Mau te Titi Mo Ake Tonu Atu Research Project being undertaken by Rakiura Maori and the University of Otago, towards assessing ongoing sustainability of the harvest and future threats. Analyses of eight muttonbirder harvest records spanning, 1938 to 2004, show that harvest rates demonstrate, systematic commonalities in seasonal patterns and broad-scale consistency in trends of chick abundance and quality across harvested islands. If co-ordinated and well replicated, harvest records offer Rakiura Maori a low-cost and effective monitoring tool of sooty shearwater reproductive success and long-term population abundance. Hunt tallies provide additional evidence of a dramatic reduction in sooty shearwater abundance from the late 1980s that was also detected by counts from boats off the western seaboard of the USA. A conservative estimate of overall decline in hunt success across diaries, for the period 1972 to 2004, is 1.89 % (CI₉₅ 1.14 to 2.65) per annum, a total reduction of 39.2%. The harvesting records show a sooty shearwater mortality event occurred just prior to the 1993-breeding season at the same time as a severe negative anomaly in both the Pacific Decadal Oscillation and Southern Oscillation Indices. The hunting diaries show a decoupling of chick size with harvest success in the early 1990s. This resulted from a decline in harvest success and an increase in its variability, while chick size remained correlated with changing chick abundance and maintained its pre-1990 average. Long- lived seabirds maintain high survival by skipping breeding and abandoning breeding attempts when oceanic conditions deteriorate, increasing variability in chick abundance is also evidence of pressure on adult survivorship. The multiple diaries confirm these were major demographic events not confined to a single island. My survival estimates for The Snares and Whenua Hou were very high 0.952 (0.896-0.979) compared to earlier estimates for this species. Transience at the colonies is high due to the presence ofjuvenile and pre-breeding birds. Both naturally high survival and the large number of transient pre-breeders indicate sooty shearwater are more resilient to harvest than earlier survival models suggested. There was no evidence for directional change in sooty shearwater breeding phenology over 49-years of harvest. Climate fluctuation/change is therefore apparently not altering egg-laying. Peak fledging occurred fairly consistently in the 2nd of May (IQR = 2.91 days). Yearly variability in emergence occurs primarily due to provisioning and localized fledging conditions. Larger chick size was strongly correlated with delayed fledging and is consistent with the traditional ecological knowledge of the birders. There was no evidence for chicks becoming smaller or that years with starving chicks were more common, so increasing mismatch of breeding with optimal forage was not indicated. The past proportion of birders over the last 20 years (1985 - 2005) has been ~2% all of Rakiura Maori. Approximately 376 birders participated in the 2006 season with an estimated of overall harvest intensity 19.4% (CI₉₅ = 13.8 - 24.2%) and a total catch of 381,000 (CI₉₅ = 262,257 - 487,186) chicks. This study found evidence that catch rates reduced with increasing birder competition partially mitigating effects on harvest pressure. The combined effects of potential climate change on bird abundance and increased harvester competition suggests that the proportion of Rakiura Maori whom choose to bird is likely to decrease as tallies reduce and cost recovery becomes more difficult. Rakiura Maori have for many years cherished and maintained their islands and implemented protective measures to safeguarded titi breeding habitat. Future harvest management will have additional issues to contend with, but Rakiura Maori are necessarily confronting these issues as the titi culture rests on the maintenance of their taonga. The information presented in this thesis shows that combining science and traditional knowledge is a powerful tool for managing harvest sustainability.

The ecology of female mallards (Anas platyrhynchos) and their broods was studied during 1988-90 on Lower Klamath National Wildlife Refuge, California. Survival of 127 radio-marked ducklings from 64 broods was 0.18 to 10 days of life, and 0.37 and 0.34 to fledging for 1988, 1989, and 1990, respectively. For the 3 years of the study, 49.2% of hens lost their entire brood; 81.2, 36.8, and 37.5% in 1988, 1989, and 1990, respectively. Ninety-three percent of mortality occurred on or before 10 days of life. No significant differences were detected in the proportion of radio-marked ducklings lost from early hatched or late hatched nests. A variety of predators consumed radio-marked ducklings; however, 49% of the cases of mortality were a result of an unknown predator. During 1989 and 1990, 3 radio-marked ducklings from 16 hens which appeared to lose their entire brood were fledged by other brood hens, and of 29 radio-marked ducklings that reached 44 days of life, 6 (20.7%) had joined other broods. Movements, home range, and habitat use were determined for 27 radio-marked broods. Relocation movements (>1000 m in 24 hrs) occurred in 12 of the 27 broods, primarily in the first week and after the fourth week of life. In 1989, significantly fewer radio-marked ducklings from broods hatching in permanent marshes survived to fledge compared to those originating in seasonal wetlands. Mean size of home ranges was 1.27 ± 0.47 km² and 0.62 ± 0.21 km² in 1989 and 1990, respectively. Most habitat selection by brood rearing hens occurred at the second order, (selection of home range area). Hens selected seasonally flooded wetlands with a cover component and avoided open or permanently flooded habitats. Estimated recruitment (females fledged/adult female in the spring population), proportional change in population size, and number of fledged young varied markedly during the 3 years of the study. Estimated recruitment was 0.31, 1.26, and 0.83 for 1988, 1989, and 1990, respectively. The estimated proportional change in population size ranged from 0.73 in 1988 to 1.29 and 1.04 during 1989 and 1990, respectively. Number of fledged young ranged from 915 in 1988 to 6,102 in 1989. Movements, habitat use, and survival of postbreeding radio-marked mallard hens were also determined. From mid-April to early August, 5,279 exposure days without the loss of a radio-marked hen were tallied. Of the 4 hens which emigrated from the study area, all were unsuccessful in rearing a brood. Unsuccessful hens moved to surveyed areas north of the study area significantly sooner than successful hens. Canals were the primary habitat utilized by postbreeding hens in 1988 while mixed seasonal and emergent permanent marsh were the most frequently used habitats in 1989 and 1990. Open seasonal and mixed seasonal marshes were the most frequently utilized habitats by incubating hens. Radio-marked hens moved a mean distance of 1,350 m from the nest to suspected feeding areas. / Graduation date: 1992

Bicknell's Thrush is one of the rarest species of breeding bird in North America. In this study, we conducted a characterization and classification of the habitat for Bicknell's Thrush on two high-elevation sites in the Estrie region, Quebec: Mont Megantic and Mont Gosford. To identify habitat preferences, we characterized and compared the vegetation composition and habitat structure of 42 sites occupied by the species, and 19 unoccupied sites. / To classify the habitat on the two mountains as suitable or unsuitable for Bicknell's Thrush, we used a Geographic Information System (GIS) to integrate Thematic Mapper data (bands 3, 4, 5, and 7) with field observations on the locations of occupied and unoccupied sites. The supervised classification of habitat on each mountain identified sites that were occupied or unoccupied by the species as suitable or unsuitable, respectively, with an accuracy of 89 to 90%. The results indicate the usefulness of our methods in mapping potential suitable habitat for Bicknell's Thrush at the local scale. (Abstract shortened by UMI.)